The record-setting day (and night) of college basketball saw 3.4 million hours of live streaming video and audio by 3 million unique visitors, up 20 percent when compared with the first day of last year’s tournament. CBSSports.com said Thursday’s totals marked the largest single day of traffic for a live sports event on the Internet.

CBSSports.com also said its Dilbert-themed “Boss Button” was clicked more than 1.7 million times Thursday.

The most watched game on day one was BYU’s 99-92 double-overtime victory over Florida, which clocked 521,000 hours of streaming video and audio, 50 percent higher than 2009’s most-watched first-day match-up, Washington vs. Mississippi State) which totaled 348,000 hours.

And the most-watched hour Thursday was 2 p.m.-2:59 p.m. ET, with 533,000 streaming hours, or 16 percent of the total for the day, peaking at 2:45 p.m. with 147,000 streaming hours from 2:45 p.m.-2:59 p.m.

CBS News and Sports president Sean McManus said:

NCAA March Madness on Demand continues to regularly exceed our expectations. It is the perfect combination of programming and the Internet. Our ability to successfully develop the product alongside steady growth in streaming programming for the Internet and wireless content provides many options and truly maximizes the network’s NCAA bundled-rights agreement.

NCAA senior vice president for basketball and business strategies Greg Shaheen added:

The continuing evolution of NCAA March Madness on Demand gives our fans even more reasons to stay connected to the tournament on a daily basis. Tremendous first-round games, enhanced features in the MMOD player, and solid early traffic numbers all point toward an exciting few weeks to come.

And CBSSports.com senior VP and general manager Jason Kint concluded:

With a number of thrilling finishes yesterday, there was little doubt that we would set another new record, as March Madness on Demand provided millions of fans with the ability to follow all of the action.